Data Sufficiency can be a major obstacle for any GMAT student, but one advantage that you have against this infamous question type is that every Data Sufficiency question has the same answer choices. One of the first steps towards success on the GMAT Quantitative section is to learn and internalize these answer choices, but another huge advantage you can give yourself is to internalize the method for eliminating wrong answer choices once you’ve started to determine sufficiency for the statements.
In case you haven’t committed them to memory yet, here are those familiar choices:
(A) Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient to answer the question asked.
(B) Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient to answer the question asked.
(C) BOTH statements (1) and (2) TOGETHER are sufficient to answer the question asked, but NEITHER statement ALONE is sufficient.
(D) EACH statement ALONE is sufficient to answer the question asked.
(E) Statements (1) and (2) TOGETHER are NOT sufficient to answer the question asked, and additional data are needed.
Let’s say you run into the following problem:
1. Is positive?
If you, like most students, look at statement (1) first, you’ll probably say to yourself, “Well, if x is greater than 5, then x must be positive!” and you’d be right: statement (1) is definitely sufficient to answer the question. But before we move on to statement (2), what does this mean for our (A)-(E) answer choices? Well, since statement (1) is sufficient, we can eliminate all choices that would require statement (1) to be insufficient, and that’s choices (B), (C), and (E).
Similarly, if you had a question where statement (1) was NOT sufficient by itself, you could immediately axe choices (A) and (D), since both of those choices require statement (1) to be “sufficient ALONE” to answer the question. And what if NEITHER statement ALONE is sufficient? Well then, we’d be down to (C) and (E) as our only possibilities, with a final answer hinging on the sufficiency of the statements in combination. (The system even works if you look at statement (2) before statement (1), you just have to eliminate slightly different choices. Try it!)
Memorizing this simple method is a cornerstone to mastering Data Sufficiency; using it means you never have to waste valuable time deciphering the intricacies of the question type itself, freeing up valuable time and effort for mathematics and critical thinking. Plus, as with any elimination strategy, it makes guessing much more efficient. If you can eliminate 2-3 answer choices and end up with a 33-50% chance to guess correctly on Data Sufficiency questions—rather than a 20% chance with a blind (A)-(E) guess—it really adds up in your final score.